Printed articles and methods of printing are well known in the arts. Articles printed using multiple station presses and color palettes of multiple inks are also known. Half tone and full tone printing is utilized to decrease and increase the intensity of particular colors in the appearance of the finished article. Composite appearances, wherein combinations of the colors in a limited palette of inks are printed to yield a color outside the palette are also known. Inks are specified using either an L-a-b value, an L-C-H value, or an L-C-H-a-b value. A delta-e value (dE) for each ink color is also specified to provide the color variation which is acceptable for each color of the printing ink palette.
The dE for each color represents the extent by which each ink used may be separated from the color actually desired in a map of the overall color space. The variation can be considered a distance between the desired and actual colors. Delta-e is expressed as a magnitude only, with no directional component supplied. Because of this form of specifying the ink color, the actual tolerance for ink color variation is a sphere within the color space having a center at the position of the desired color and a radius of delta-e. In applications wherein the colors of the finished article are composites of the underlying palette, it is common for the cumulative effects of the base color variations to result in composite colors which exceed the accepted level of color variation from the desired composite color. Such an excess variation may result in a rejection of the finished article.
What is needed is a method for printing articles wherein the specification of the ink palette colors will result in the use of appropriate inks yielding printed colors which are within the acceptable color tolerance limits of the desired colors.